Structure light micro-nano structure three-dimensional detection method based on composite grating

Abstract

The invention discloses a structure light micro-nano structure three-dimensional detection method based on a composite grating. The composite grating formed by a horizontal sinusoidal grating and a sinusoidal grating inclined at a certain angle theta projects structure light on a surface of a tested object. During a process of horizontal scanning of the object to be tested, CCD synchronously collects modulated fringe image sequences from a conjugate light path through a beam splitting prism. A grating line direction of a horizontal grating is vertical to a horizontal scanning direction, and ahorizontal displacement of an entire field modulation degree of the object is extracted and calcualted to realize high-precision pixel matching of the image sequences. An imaging focal plane positionof an inclined grating is inclined and fixed. During a horizontal scanning process, phase shift and vertical scanning can be realized continuously, automatically and synchronously. The inclined grating is used for single point modulation degree extraction of the object, and height information is acquired to realize high precision micro-nano three-dimensional detection. In the invention, the objectto be tested is horizontally scanned so that a large-range and high-efficient three-dimensional measuring process can be realized, and the method has a good application prospect in the micro-nano detection field.

Description

technical field [0001] The invention belongs to the technical field of optical microscopic imaging and precision detection, and in particular relates to a three-dimensional detection method for structured light micro-nano structures based on composite gratings. Background technique [0002] Micro-nano devices refer to functional devices with a scale of micron and nanometer. The application in the technical fields of microelectronics, biotechnology, aerospace, and metamaterials has developed rapidly, which has greatly promoted modern life and social production. It will be a hot spot in the development of science and technology strategy in the next period. The three-dimensional appearance of micro-nano devices is directly related to the performance characteristics, reliability and functional analysis of the product. High-precision and fast micro-nano detection methods and technologies are important means to obtain the three-dimensional appearance of micro-nano structures, and ...

AI Technical Summary

Problems solved by technology

[0005] Aiming at the disadvantages of low efficiency and complex structure in the existing three-dimensional shape detection method of micro-nano structure, the present invention designs a three-dimensional detection method of structured light micro-nano structure based on composite grating: in this method, A composite grating combined with a horizontal sinusoidal grating and a sinusoidal grating inclined at a certain angle θ is used to project structured light on the surface of the object to be measured. During the process of horizontally scanning the object to be measured, the CCD synchronously collects the modulated light from the conjugate optical path through the beam splitter prism. The fringe image sequence, combined with the continuous 3D reconstruction algorithm, can reconstruct the 3D surface shape of the micro-nano structure, realize the large-scale detection of the continuity of the micro-nano structure, and can be applied to the online detection process of the micro-nano structure, and the detection accuracy can reach the nanometer level

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